A memory device includes a plurality of memory cells. In some cases, it is necessary to prevent access to part of the memory cells by a third party such as a consumer. In Patent Document 1, a memory is disclosed in which data cannot be read without inputting a predetermined keyword. A third party cannot read the data because of the necessity of inputting a keyword.
[Reference]
[Patent Document 1]
    Publication of Unexamined Utility Model Application No. H2-14150